Wave Height Models Calm the Shipping Waters

Just as truck drivers want to know about road conditions and airline pilots are concerned with foggy skies, ship captains have an urgent need to know about wave heights – as do surfers and others who spend time on the seas and shores. A Texas A&M University at Galveston professor has spent his career studying large waves and what causes them.

Vijay Panchang, Regents Professor at Texas A&M's branch campus by the sea, has been researching waves for more than 25 years and has developed modeling systems that can predict wave heights in several types of conditions.

He has developed wave prediction and coastal circulation models that have been used by numerous maritime engineering groups from Maine to Texas. Such information can literally be a lifesaver for all sizes of ships, from recreational fishing boats to oil tankers that are as long as three city blocks.

Using data from NOAA and his own complex models, Panchang can provide wave model predictions for much of Texas' 367-mile coastline, and also projections for much of the Gulf of Mexico.

"The models are based on a variety of information such as wind speed, wind direction, seabed topography, offshore weather conditions and other factors," Panchang explains.

"Such information can be useful to anyone on the water at that time. But we can also use wave information in engineering design and to predict sediment transport."

Current wave models cannot predict tsunamis because they are caused by other physical causes such as sudden movements of the seafloor due to earthquakes.

But his modeling system was able to predict accurate wave heights during Hurricane Ivan in 2004. In that storm, buoys recorded 60-foot waves off the coast of Alabama.

He says it is also difficult to predict "rogue" waves that sometimes pop up in the Gulf but can occur all over the world.

Rogue waves are waves that are considered unusually large for a particular region or "sea state," and they usually occur far out at sea. They can be especially dangerous to ships, even large cargo ships or cruise liners. They can also happen on lakes, and numerous ones have been reported in Lake Superior, Lake Ontario and other areas of the Great Lakes.

Rogue waves can reach enormous heights. One of the most famous incidents involving a rogue wave happened on Dec. 13, 1978 with the German ship MS Munchen. The cargo ship was in the North Atlantic when it issued a distress call and moments later vanished. An investigation concluded that a rogue wave between 80 to 100 feet high hit the ship, likely breaking it into pieces and causing it to sink, killing all 28 crew members.

"Rogue waves can be impossible to predict because no one seems to know exactly what causes them," Panchang says.

"We do know they can reach 100 feet high and perhaps even higher than that. We try to predict wave conditions that we know about, and where the data is in more of a controlled state.

"When Hurricane Katrina hit in 2005, it rewrote much of what we had believed about waves," he adds. "It produced conditions that we did not think were possible, but it gave us critical new information about wave structure and movement.

"In the past, some waves were called 'hundred-year waves' because it was believed that such waves only occurred every 100 years or so. But the hurricanes of the past decade or so have shown us that is not true – they can occur much more often. They have given us information that allows us to give more precise models about waves and how strong and high they can be."